Direction finder



July 3, 1928.

H. J-. J. M. DE R. DE BELLESCIZE nmsc'rron FINDER Filed Aug. 29, 1921 3 Sheets-Sheet l HJ. .M. DER. DeBELLESCIZE 33n h 1$ (1120mm; L

July 3, 1928. 1,675,332

H. J. J. M. as R. DE BELLESCIZE DIRECTION FINDER Filed Aug. 29. 1921 s Sheets-Sheet 2 gwven to:

H.JJ.M.D R. 00 BELLESUZE July 3, 1928. 1,675,332

H. J. J. M. DE R. DE 'BELLESCIZE DIRECTION FINDER Filed Aug. 29, 1921 S Sheets-Sheet 3 anvawtoz H. JJ. DR. De BELLESCIZE ,nn nnr JEAN Application file aosnrii 'rxianrnbe emes]; be ermane, for ioifnon, 'iiRANon.

ninnc rron "ri'rfnnn, v

d August 29, i-earseriai in. 496,537, and'in' Fr an'ce Ma 11, 192'0.

emn'r'an manna THE 'rnovrsrons on THE Acr'er'nancn 3,1921, 'ns'ra'rxn 1313.

The invention relatesto a method oteliminatmg the 180 degree douhtin the radiogoniometrical deterniina of a sending station and means by which efficient use may he ma this method.

-' According to the presen 'ceiving frame or loop ant 'may he balanced standpoint for the pn 'ner particularlydescribed in Fr rpose and "in the No; 495,316 and its additions.

According to the present invention, successive observations to =point'of minimum response are made, the

' firstone'with a balanc determine tion of the direction also to the specific de of t invention, a reenn'a isu-sed and from an electrostatical man en ch Patent,

two the ed 'lirame and the second with an unbalanced frame. This is done forthepurpose of determ ning whether the first observatlon is correct or whether to be corrected by 180.

''the angle of'digression hetweenthe :pla

the loo When 1 mace and the plane' first observation is In In "the following,

it is The direction of no of the second observation s oithe loop when the ade i-s utilized in this frangemen'ts will he described for ohta invariable harmony betw e arin'rng een the direction of the angular (llQ'lQS-SlOnHnCl the 180 degree correction and also "for angular digression to in securing a SLll'l'lClGI'lt ermit the appl1ca-' tion'o'f the method with certainty. Further- Fig. 1 shows the con 'to the detecting and in Fig. 2 1s a graphical illustrat 'the balanced.

Figs. 3

the app ara tus. v

plaining the operation of the device.

'Figs. 4,6, and 6 are modifications o 7 -dev1ce as shown in Fig. 1.

the steps will he'descrihed which must when practicing V the invenof establishing and usnections of the frame ducting apparatus.

ion showing characteristics ofthe antenna when unand 3 are diagrams used in ex- 1": the

Two circuits are superposed on the receiving frame which directly or indirectly ates the detecting and indicating'system One isthe normally closed circuit which iv the total cha'r e of the mass and the grou The open 7 circuit w the apparatus.

actuistraversed hy a current 'that'does not modicircuit which is rcul ating between t on trode "tube.

.qucncy w and-the fpendin g on "the "precision with which the receiver is tuned. A

by closing the switch 1 sin direction of propagation the'telephone or other detector of the directhexcapacitiesindividual to the detecting and 7.

indicating apparatus connected with the terminal a and scheinatica lly v representedby "the elementsof '?a three electrode tube connected tothis "terminal, i. e. the filament and the heating battery S the "pl ate hattery S thetelep'hone t, and theiplate u. 'lVhen the frame is balanced, theelectrombtive force generated by the variation of flux through. the closed circuit is the only o'ne thatis fefi'ectiveon the'grid or the'three-elec- This will assume the for-in of v X sin Z sin(wt+1e) The amplitude X depends on the" total surface ofthen'frame, Z is the angle formed by the plane of the turns with'the magiietic field, i isaphase product of the angular fretime 't, e, is a'phase dethe time chosen as origin and The action of signals on'thedetector indicator system is thus annulled by two; values or" Z ;-xZ ='O and Z -l'SO (FigiQ'). The po- 'sition er the sending station willtherefore be. known to hem either of two directions at angles of 180 degrees.

:Hthe fraine'i's unbalanced, e. (Fig. 1) to connect terminal acof condenser C to ground and opening the switch 1?, asa result of the unsymmetry of 'therg'round connection, an additional force Y sin(uit l-'r) superposed 'on the normal efiect: of Zsin (w fi r'e) whereby'the total efiect form an (w Y ant-(waft).

I he graphical illustration inFi'g. 2 shows a .the characteristics of the antennawhfen unbalanced; The diametric'al iline in such figure is assumed to he at right angles to the "of the' nconnng signals so that the .lines'QZ 'an'd-O'Z' indi' cate the positionsof the frame :coil of theta-ntenna whenitis at angles of 0 and 180 re 'spectively with the .plane of the magnetic field. The other broken lines extending radially from the center of the circle indicate positions of the frame coil at angles Z and Z respectively with the magnetic field. In each of the last named positionsof the frame coil, the electromotive force induced in the loop of the antenna by the magnetic field is indicated bytheline X sin Z sin (wt-ts), it being assumed that the signal is coming from the right of thefigure, and the voltage due to the antenna efltect of the frame coil in itsunbalanced condition is indicated by the line Y The force Y sin'(wt+ 1s genrows on Fig. 2, but variesin magnitude ac- I magnitude of the resultant R cording to the angle of the frame coil with the plane of the magnetic field. The electromotive force Y sin (mt-t on the other hand, is constant both in phase and magnituderegardless of coil. Accordingly, when the-frame coil is rotated the magnitude of the resultantR of the electromotive forces X sin Z sin (mt-FE) and Y sin (wt-t passes through a minimum value at positions of the frame coil depending solely on the magnitude-of the electromotive force X sin Z sin (wt-l e) It will further be understood from at its minimum value depends upon the angled which indicates the phase of the antenna effect voltage I 1 Sin (wi ty).

, directions indicated by If the frame coil is rotated from the positionZ or Z", in a direction opposite to'the the arrows in Fig. 2, the phase of the'electromotive ,force'X sin Z sin (wt-Fe) .will be opposite to thatindicated by the vector in Fig.2. 1 The resultant R, therefore, ofthe voltage induced in the loop of the antenna by the magnetic field and the antenna effect voltage will continu ously increase as the loop is turned from the position Z or Z, and will bemuchlarger than when the loop is rotated to one of the positions indicated on the vector diagram.

This property is to" be utilized for removing the doubt of 180 degrees that exists con cerning the direction of the'signalling station. Therefore,-it is necessary that (a)'-The direction in which the frame rotates when passing .from the position of 'minimum response with the balanced circuit the corresponding position arrangement to 'ciently great absolute value to avoid errors the position of the frame Fig. 2 that the Icuit oft-he antenna is that if the tuning of (b) The difference (Z Z have a su'fiiin observation. (0) The direction of rotation given tovthe. frame in passing from the position of minimum signal with balance to the position. of minimum response without balance must be ascertainable by a simple rule to determine sition of'minimum response with balance/to the position of'minimum response without balance follow an invariable law.

whethe'r the first reading was correct or er- It is necessary and it issuflicient that the I respective waves A tuning of the closed resonator maintain, a well defined relation with regard to the wave that is to. be received.

The closed resonator should be tuned to the signal and this will at least beapproximately the case. Vith respecttothe open system, its own wave a, may, for example, be inferior to )t. The inequalitya v may always be easily produced. It may be brought A corresponding to the resonatorand the open about, if necessary, by providing (Fig. 4) a condenser C in thelground connection to unbalance the apparatus. v

one as Well as tneotner,

The double condition ()t and the adjustment A A produced in turn by. the construction of the aparatus) will insure that the directionrof the definite lawiwhich may be made use of to remove the doubtof 180 degrees.

If the tuning. of the open circuit is changed, thephaseof the antenna effect voltage Y sin (mt i'y), as indicated by the angle a in. Fig. 2, is 'varied. If, for example, the open circuit is tuned to awave length A which is equal to the Wave length A to .be received, the phase of the. antenna effect voltage Y sin (wtn y) is at 180 from the vector X sin Z sin (wt Fe). It will; also be apparent from Fig. 2 that if the tuning of the. open'circuit of the antenna is varied from a 'wave length corresponding to the phase angle rotation will follow a a to a wave length'more nearly approaching V the closed cirtuned,-the' angle a of the antenna effect voltage willbe decreased, thereby causing the minimum resultant R of the electromotive forces in the closed circuit and the open circuit varied both in magnitude and phase. Moreover,it will also be understood from Fig.2

the open circuit of the antenna is changed so that the wave length A of the open circuit is reversed with relation to the wave A to be received, that is, if it ischanged from avalue lessthanna to' the wave lengtha to which of the antenna to be avalne greater than A-orvi'ce -v ersa, theiposi- 'ti'on'of theline- Y-sin (at *i'ry) will' be'changed to the opposite side oft-he angle-tothe ector $111 2 "sin (mt-ts), so'that it'he result-ant Rot the electromo'tive forces} int-he framecoil of the antenna -will be} caused *to o'c'cupy --a'p-osition" at the opposite sidero'f the vector X siIfZ sin (QZH- a). "It isimportant, however, as w ll ap pear more'clearly hereinafter, that, in "order that readings may be r eliably and "readily-takenythe minimum resiiltant R shall be astconstantns practicable *bothin' phase andma-gnitude. Gonsetpiently as indicated 'aboye,*thewavelength to which the open circuitfio'f the "antenna; is tuned 'shonldibeara' substantially constant-relation "with the wavelength which is being re- "oeive'cl. 1

In order to establish the rules necessary for the practicahuse, is indispensable that the law --in* question" be known. First of all, it is apparent ig. 3 thatwhen frmnone position 1x corresponding to "the minimum response With balance to the position which is the-nearest *tothe preceding and corresponds to the minimum frespon-se with -ui'ibalancing, the direction of -rotation of the frame rnust,"for example, always be such that the-first half rotation of the 'coilL directly connected with groundapproaches the sending station which {in "Figs. 3 and "3" of the drawings" is assumed' to' be at the leztt of the sheet. "Thisl-aw is'easily verifieclf by 'means of a iew signals sent fromlstations that-are known. a p I j Theconditions to be o ta i ne'd in order that the rotation Z ZJ of the frame-becon- "clnsiveare as follows. A rotation by-at'least 15 degrees is -absolutely necessary "'for eliniinating" the errors arising front mediocre observations. p Interpretation ofthed'otation effeeted'by the trame whenpassin'gdrom the re'a-"di ng-{Z (balance) to the' reading Z (unbalance).

The voltage Y sin ot+ 7) must be-made as'great-as possible -=With respect to the force sin Zgsin (mt-H). 1n otherjwords, the

' reading Z must be made under "conditions l n the eircnits dt Fig-s. 1,4 and- 5, "the switches P, P ha-vin a common control- =ling' means must 'be simultaneously moved into position 1 for the reading of the angle Z and into theposi'tion 2 for the-reading of Z I-npositionQthe following unsymmetrical conditions arise:

The balancing condenser C is disconnected, whereby the additional potential at b of the open oscillator is increased.

The other terminal of the amplifying and detecting system is connected directly to ground, i. e. to a source of potential.

The potential developed in the Whole frame is, if necessary, increased by an auxiliary selt inducti0n coil L (Fig. 5) but With- {reading Z (balance) to ground is to that maybe "dina'l axis of abo'at. v tablished once "for all by observing 'resulting from known "ClI gTQSSIOH;

operator Whofis assumed to be looking in to obtain the true'digression.

In order to understand how the'rot'atio'n efi e'cted by the frame When-passingtrom the to the reading Z un-i balance) may be interpreted, let us '-assume that the ap -iaratus isa djusted for the'nsual operating conditions that'the' movable frame is before a fixed index; and that angular readings increase when the frame is .turned in a clock-Wise direction.

VAs shown in "Fig.3*,whe1tpassing from the reading Z to the reading Z theirame turns in a clockwise direction (increasing angles) when the first' halt-coil L connected the left hand of an observer "who is assumed to be looking'in'the direction of the sending station,and in counter clockwise "direction "it-decreasing angles) when the half coil L 'In' orderto obtain from this asiinple rule put topra'ctical'use, it isadvisable is to "the right "hand that the graduations belesta'blisheddn ac-.

cordance with a conventionalanduniform the angle indIcated by rule. VFor instance,

the index mnstbe equal to =the'real' digres-' sion -for the suppression obtained fwit'h'fa balanced frame,the 'first h'alt co'il 'tlrat is most directly' connected with ground being to the left hand otthe assumed observers 'Thisrule of construction may ot 'courseflbe ried for geographicat surveys as 11 i to the longitu- V for digressions *Withrespect The rulemay be essignal S lrame must be balanced,"-'tuned' and' 'pointed in I a :ma'nnerto destroy the signal; the-directgroundedhalt-coil being to theletto'tan the direction P of' th'e sending station. The

*known digression is placed in front the index on the graduated plate and thus, the 'z'ero point of thegradu'ation isdetermind.

Fmthe obseri'iation of actual signals,

' the following rules are to :be observed.

If the two successive readings Z and "Z are such that Z Z (Z.- 'Z ),-the angle Z is correct.

A simplified "arrangement is" shown in Fig.

6 'for' practicing the pri'neip'le'ot i the method previously described and has certain advantages in the practical application of the method.

' The It Will be noted that the method described is based onthe inequality of the electrostatic capacities existing between the terminals of the receiving'frame and ground.

According to the present modification, for

the purpose of ascertaining the exact digress10n he exactness being characterized by two suppressions separated bypl 80 degrees I and by the equality in ex'ten'tiof the two planes of suppression), the symmetry of; the frame is obtained in a, manner, that s imperfect rin theory but suiricient in practice, by groundinga point near the centre of V .the :antenna self induction coilr This opera coil of the frame.

.plies' current to ation stabilized the potential. of r the frame andattenuates its effect as an open antenna.

The simplified arrangement is arranged in the followingmanner." Themovable-frame 11 forms aclosed circuit With the variable condenser 12. op-

erating a switchl3, ground may .be connected to a suitably chosen-point. (more or lessnear the centre) of the selfinduction The condenser 12 isconnectedthrough conductors 14 and'15 to the terminals of .the receiving apparatus, di-

agrammatically illustrated by a three-electrode jtube 16, but usually this apparatus comprises a complete amplifying, and -de-.

tectingv system. 17 is a battery that sup the receiving apparatus connected" through: a trans- Which are e. g.

-- former 18 with the indicating apparatus 19 (telephone,

galvanometer, etc.) The installation is completed by, a small Faraday cage 20 enclosing all the ap-paratusand circuits with the ell understood exception of the antenna and the indicating apparatus.

The conductor leadingto the. switch 13- is connected with the Faraday frame.

In orderto produce the desired unsymmetry necessary for the removal of the doubt, the, capacity provided between the" F aradayframe'andl the apparatus (ampli-' fiersgbattery, etc), connected With conductor 14 of the condenser '12 is adjusted. The conductor .15 is connected to a simple grid Without appreciable individual capacity. Then the switch 13 is open, the natural unsymmetry of thecircuits modifies the digression byabout fifteen degrees and this angle is sufficient for removing the doubt existing concerning the digressions, the direction of the digression variation being the one describedin: the main patent.

IIaving described my invention, What I claim is '1. A direction finder comprising a loop antenna, a tuning element therein, a detectorcircuit connected .to said tuning element, a ground connectlon connected to one side of :the tuning element containing a capacity tuning element and a tional antenna. to

adapted to balance the .capacity of said dc-, i

tector circuit to groundor'its equivalent, a

second connection onthe other side of'the i i switch for connecting said side to --ground tounbalance' the capacity of the loop to, ground or itsequivalent;

'2. A directionjfinde r comprising a loop I antenna, a tuning element therein, a. detector circuit 1 connected to saidtunmg element, a

;ground connection connected to; one side of the tun ng elementcontannng a capacity adapted to balance the capacity of said detector .circuit torground or its equivalent, a second connection on the other sidegof the tuning element and a switchfor connecting said side to .grouncl to unbalance the capacity of the loop to ground or its equivalent and an impedance in said second ground connec .tion.

3. In the method of 'ascertaining the direction of a transmitting stationfrom. a receiving station with a loop antenna func and at another time as .a combined directionaland non-directionalantenna, the steps tioning at one time as adirectional antenna which comprise, electricallybalancing: the v loop antenna and setting'the sameas a directional antenna to thefpoint of minimum signal reception, said loop antenna and setting the same asa combined directional and non-directional antenna'to the point of minimum signal reception, and-determining from the; direction of digression between-these two points the sense of direction of the transmitting station.

, 4C. In the method of ascertaining the direc tion of a transmitting station from a re-' ceiving station with a loop antenna. func tioning at one time as a directional antenna and at,another time, as .a" combined gdirec-n the steps electrically, balancing the tional and non-directional antenna, which comprise, loop antenna and setting the same asa-direo the point of reception of a signal of'predetermined strength, then then electrically unbalancing i electrically unbalancing.. said ,loopantenna and setting the same Iasa combined directional and non-directional antennalto the po nt of receptlon of a signal ofsa dpredetermined strength, and determining-from the direction of digression between jsaid points the sense of direction of the transmitting station. I I Y HENRI JEAN JOSEPH MARIE de REGNAULDi dc BELLESCIZE. 

